Key structure for tear strip containers



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Feb. 21, 1956 M. R. WILKINS KEY STRUCTURE FOR TEAR STRIP CONTAINERSFiled July 8, 1953 1N VENTOR ATTORNEY -ein United States Patent O KEYSTRUCTURE FOR TEAR STRIP CNTAINERS Margaret Ruffin Wilkins, Greenville,Si. C. Application July 8, 1953, Serial No. 366,835

1 Claim. (Cl. 22B- 52) This invention relates to an improvement in thosetypes of keys adapted to remove tear strips from certain kinds of vacuumpacked tins such as coffee tins. More particularly, the inventionrelates to a key having opposed double prongs between which the tearstrip is positioned in such manner that it will not slip off the end ofthe key or become disengaged therewith.

Various types of keys have been devised for this particular use;however, either they are impractical to make because of the inordinatecost, they are subject to fracture easily, or they do not obtain theadvantageous objectives of the instant invention.

It is also an object of the invention to provide a key of the typementioned wherein such opposed pairs of projections terminate inrelatively sharp points so that during winding of the tear strip on thekey the latter has a positive means of traction which quickly overcomesthe resistance of the tear strip to removal from the can.

A further object of the invention is the provision of a key of the typementioned which can be fabricated of stamped metal at exceedingly lowcost, and yet which will be comparatively durable and sufficientlystrong to elfectively remove such tear strips without twisting orbreaking.

Other objects and advantages of the instant invention will be understoodfrom the following description and the drawing forming a part hereof,wherein:

Figure 1 is a plan view of my improved key, picturing it as attached tothe top of a sealed tin such as a coffee tin;

Figure 2 is a section view taken on the line 2 2 of Figure l;

Figure 3 is a perspective view of the invention shown in Figure 1,illustrating the manner in which the tear strip is wound between opposedpairs of projections; and

Figure 4 is an enlarged perspective view of a portion f of the key shownin Figure 3, illustrating the manner in which the opposed projectionsmay be provided with the sharpened points to add to the tractivefunctions of the key.

Having now more particular reference to the drawings, the typical tincontainer is illustrated at 1. Such is usually provided with aconcentric depression at the central portion thereof, herein designatedat 2.

Viewing Figure l, it will be readily appreciated that the entire key maybe fabricated with a single stamping out of sheet metal of sufiicientthickness to resist bending when the key is used. As a matter of fact,the sharpened edges, to be referred to in more detail hereinafter, canbe formed by the same stamping process.

In so manufacturing the device itis, of course, provided with a handle 3consisting merely of a rectangular formation provided with an enlargedopening 5. The opposite end of the key terminates in a projection orextension 6 which is suitable for attaching, by soldering or othermedium, that end of the key to the top 2 of the can. As indicated at 7,a suitable crimping between extension or tip 6 of the key and theremainder thereof appreciably weakens the interconnection therebetween.This enables the key to be bent upwardly, when desired for use, so thatit breaks at this point from the extension 6 which, as stated, ispermanently affixed to the can top. This operation is perfectly apparentfrom Figure 2 wherein the key is shown in solid line in its fixed andhorizontal position and wherein it is depicted at B in a lifted orangular position approximately sufficient to break it from its securedextension 6.

The main body portion S of the key is provided with two opposedshoulders or triangular formations 10 and 11. Each of these terminate attheir inner edges in points 12.

Between these shoulders is positioned a shank 15 provided with a slot16, the latter being adapted for reception of the free end of the tipstrip toinitiate the winding again of the latter upon such shank 15.

1t is seen that the inner faces 17 of the respective triangularformations or shoulders 10 and 11 are parallel to each other and thusform what might be termed retaining rims. Actually, although the entirestructure just described is flat in formation the two triangularportions lii and 11, together with the shank 15, form what might beviewed as a winding spool suitable for reception of the tear strip.

These triangular arms 10 and 11 with their respective points 12, alsoprovide leverage for winding and serve to tighten, through the sameleverage, the strip as it is wound around the shank 15 of the key, thusproviding a uniform and smooth coil throughout the winding operation.

Thus the triangular formations 10 and 11, forming an integral part ofthe key, serve to contain the strip of metal therebetween, therebyeliminating the tendency of the strip to slip olf the key in anunmanageable coil making further winding impossible. This operationshould be readily understood by reference to Figure 3, wherein it isseen that the strip 2t) is formed in a precise and even coil within thetwo triangular shoulders 1l) and 11.

A modication of the invention is shown in Figure 4. Here each of thepoints 12 of the two opposed triangular formations 1li and 11 issharpened somewhat, resulting in comparatively pointed projections 25.This may be done, as stated, either during the stamping process or thekey can be honed at these points in a degree sufficient to render thesame more pointed than those shown, for example, in Figures 1 and 3.With the four projections 12 sharpened somewhat in this manner it is tobe appreciated that they provide considerably more traction against theusual smooth surface of the common type of vacuum tin. In any event,Whether with points shown in Figure l or those shown in Figure 4, theprojections 12 are such that they facilitate an immediate grasping ofthe surface of the can and an immediate tearing and winding effect uponthe tear strip.

The operation of this invention should be apparent from the foregoing:The key is disengaged from its soldered tip 6, affixed to the can, andthe metal strip on the side of the usual metal container is insertedthrough the slot 16. When the handle 3 of the key is turned the shaft orshank 15 and the four projections 12 are brought into play in a circularwalk around the can, the strip being wound and retained within thetriangular arms or rims 10 and 11 much in the same manner that wirecable is wound upon a spool. Leverage for winding and tightening isadditionally furnished by the points of the projections 12 and pressureof these relatively sharp points against the side of the can. When thearc around the can is completed the key is discarded.

It is apparent also that this key can be manufactured n various sizesdepending upon the size of the tin desired tobe used. YThe distancebetween the slot 16 and the end of the projections 12 may also vary withthe circumference of the can, the controlling factor being provision ofsuch distance as.to contain the entire rolled strip within suchprojections I tis to beunderstood that the instantrinventioneithibitstwo primary and critical factors not found `in previous related devices.These are firstly, the ability vto wind the ,tearstrip upon the keywithout possibility of slippage axially therefrom, and secondly, Vtheadded traction supplied by the relatively sharp projections 12, thelatterY feature contributing materially to the more expeditious removalof such strip from containers of the type described.

While a preferred embodiment of the invention has been shown, it is tobe understood Ythat vvarious vlrnodiiications thereof may be resorted towithout departing from the spirit and scope of the appended claim.

What I claim is:

In a key for removing a tear st rip from a can, a main s 4 Y t bodyportion, a handle at one end of said portion, a @retable ,tip ,at theaber @il thereof., ,a ,lqnstasliaal slot in said body portionintermediate the ends thereof for the reception of the end of a tearstrip, opposed pairs of spaced triangular shoulders having facingparallel sides projecting from opposite sides of said body portion, withthe ends of the slot in alignment with said parallel sides, theoutermost ends of said shoulders terminating in relatively sharp pointsfor engagement with the surface Aof said can, said shoulders ,extendingoutwardly a substantial distance beyond the sides of said body portionand forming abutments between which a tear strip is rolled when removedfrom thepan.

References Cited in the le of this patent UNITED STATES PATENTSGrossenbach May 15, 1'9571

